1. Field of the Invention
The present invention relates to a superconducting magnet apparatus used for an electromagnetic-levitation traveling equipment and to such an electromagnetic-levitation traveling equipment provided with the superconducting magnet apparatus.
Moreover, the present invention also relates to a structure of a partition wall between windings and to a cooling system for cooling these windings, which are both necessary for practical use of this superconducting magnet apparatus.
2. Related Arts
Progress has been made in achieving practical use of an electromagnetic-levitation traveling equipment arranged in such a manner that a superconductor is used to form windings, and that a superconducting magnet apparatus where these windings are received in cooling vessels is installed on, vehicle, so that the windings receive magnetic repulsive or inductive force with respect to stator coils laid on the ground, in order to cause the vehicle to travel on a track at high speed.
Since the electromagnetic-levitation traveling equipment of this kind is required to have a light weight and to produce a strong magnetic field by means of an electric current, the magnet apparatus employing a superconductor which has no power loss has been investigated as an effective means for meeting these requirements. A superconductor may be suddenly changed from a superconducting state to a normal conductive state by a disturbance such as temperature, vibration, heat or the like (commonly known as a "quenching phenomenon", but hereinafter simply referred to as "quenching").
Conventionally, various means by which the vehicle can be safely controlled even if this quenching happens have been suggested and proposed.
For example, as disclosed in Japanese Patent Unexamined Publication No. 54-132917 (A), a method has been suggested in which when one of the superconducting magnet apparatus is provided on the vehicle is quenched the quenching is detected and the balance of the vehicle is maintained by forcedly deenergizing another superconducting magnet apparatus located in symmetry with the quenched magnet apparatus in question in order to stop the vehicle safely.
Further, as disclosed in Japanese Patent Unexamined Publication No. 57-21601(A), a method has been suggested in which sliding surfaces of emergency skids for sliding/supporting the traveling equipment structurally have configurations corresponding to configurations of armature rails so that the traveling equipment is stably set or landed on the armature rails and is safety supported even if levitation force from the electromagnet disappears.
According to these conventional methods or countermeasures to protect against quenching in the superconducting magnet apparatus of the electromagnetic levitation traveling equipment of this kind, problems in the balance of the traveling equipment in the running condition and in the stability of the equipment during an emergency stoppage are expected to be solved from the viewpoint of safety, but a disadvantage has not been completely eliminated wherein that when the superconducting magnet apparatus is deenergized or substantially demagnetized due to the quenching thereof, the magnet apparatus itself affects the stability of the traveling equipment. That is to say, although the equipment which travels at high speed by utilizing the magnetic repulsive force requires the light-weight superconducting magnet apparatus which constantly provides a great or strong magnetic repulsive force, the superconducting magnet apparatus which is quenched consumes the persistent current and magnetic repulsive force is lost so that the superconducting magnet apparatus affects the traveling equipment unavoidably as a load or weight on it. This weight of the superconducting magnet apparatus directly affects the balance of the vehicle during the high-speed traveling thereof. Since quenching may happen at any moment in the equipment which travels by utilizing the superconductivity, safety cannot be fully attained only by trying to maintain the balance of the vehicle during the high-speed traveling. Moreover, in case of the emergency stoppage in response to the quenching, necessity of re-energizing the quenched superconducting magnet apparatus is an obstacle to its practical use, because it takes very long to cool and excite the superconducting magnet apparatus again unless the apparatus is stopped near a station or on a traveling track system provided with a sufficient repair installation.